1. Field of the Invention
The present invention is directed to electric current producing cells, and more particularly to such cells having high energy density cathodes containing a plurality of cathode-active chalcogenides.
2. Statement of Prior Art
High energy density batteries have been developed based on the use of alkali metal anodes, e.g., lithium and chalcogenide cathodes, e.g., TiS.sub.2, as exemplified by U.S. Pat. No. 4,009,052 to Whittingham. In addition, recent patents suggest the use of mixed cathodes for advantageous results wherein the chalcogenide is combined with other active material. For example, U.S. Pat. No. 3,791,867 suggests the use of transition metal chalcogenides as hosts for cathode-active materials such as chalcogens and halogens, e.g., sulfur, selenium, tellurium, bromine and iodine.
More recently, in U.S. Pat. No. 4,118,549, it has been suggested that high energy density materials such as metal and carbon fluorides and some metal oxides may be used in cathodes with a layer of high ionic conductivity such as TiS.sub.2. Exemplary fluorides are PbF.sub.2 and (CF).sub.n. It was recently disclosed that Mallory U.S. patent application Ser. No. 790,724 (Apr. 25, 1977) describes mixed cathode systems employing a non-conducting chalcogenide, e.g., As.sub.2 S.sub.3, Sb.sub.2 S.sub.3, Sb.sub.2 S.sub.5 or SeS.sub.2, with a highly conductive chalcogenide such as TiS.sub.2 (only Abstract copy available); and Mallory U.S. patent application Ser. No. 790,800 (Apr. 25, 1977) describes mixed cathodes having chalcogenides such as TiS.sub.2 and other active materials such as S, Se, Te, Br and/or I. Additionally, it has been well publicized in the nonaqueous electrolyte literature that cathode materials which may be used in conjunction therewith include typically primary cell chalcogenides, e.g., FeS.sub.2, or typically secondary chalcogenides, e.g., TiS.sub.2.
Lastly, U.S. Pat. No. 3,992,222 describes mixed cathode cells having alkali metal anodes wherein the mixed cathodes contain FeS.sub.2 and a sulfide of a polyvalent metal. However, this patent is directed to high temperature batteries and, furthermore, nowhere anticipates or suggests any cathode-active material combination of the present invention.
Notwithstanding the prior art which is replete with examples of mixed cathode systems having two or more active materials including TiS.sub.2, no prior art teaches or renders obvious the present invention which involves a high energy density cathode system containing a plurality of selected chalcogenide materials more fully developed below.